A widely used procedure for adjusting the wheel alignment parameters at the rear axle of passenger cars consists in setting the specified toe and camber angles by selectively turning special eccentric adjusting screws. The eccentric movements are transmitted through the wheel suspension (toe, camber, spring link) to the hub carriers and the values to be adjusted are measured, for example, at the brake discs. The eccentric screws may also be rotated by servo-assisted drives or by tools from the field of threaded fasteners.
This procedure necessitates the provision of special adjusting tools with systems for positioning the tools relative to the adjusting screw and for interaction with the adjusting screw. If the adjusting screw is poorly accessible for design reasons, special tools (geared offset heads, right-angle gear drives) must be provided for carrying out the alignment work. To enable alignment work to be performed in short-cycle production lines, the adjusting tools must find the position of the adjusting screw automatically. This necessitates providing additional systems for the fine positioning of the tools relative to the screw.
The adjusting screws in the vehicle have to be configured as special-purpose screws. This involves additional costs. From the constructional aspect, the production process for the shift gates on the rear-axle supports is comparatively time-consuming. Furthermore, wear (abrasion) is identifiable between the eccentric screw and the rear-axle support. This puts a limit, which is dependent on the material combination axle body/screw, on the number of alignment attempts.
During performance of the alignment work, the axle may be gripped, for example, by gripping devices known from European Patent EP 1 503 363 B1. This patent discloses the use of a chuck system to support an axle's wheel flanges. The chuck system grips the axle's wheel flanges near to the outer periphery of the thrust-bearing discs for the brake discs and the wheels. The chuck system is designed such that it follows the movements relating to a change in the orientation of the axle's wheel plane.